Roller Collar Configured to Reduce Seal Packing

ABSTRACT

A roller collar is provided in a roller assembly of a machine, such as a track carrier roller of a track-type undercarriage. The roller assembly includes a roller mounted on a shaft and having a seal retaining lubricant between the roller and the shaft. The collar and an inner surface of the roller form a seal cavity placing the seal in fluid communication with an ambient atmosphere surrounding the roller. The extends over an opening into the seal cavity, such as with an outwardly extending flange or teeth or with outer surface configured to increase a distance to be traveled to enter the seal cavity, to reduce the amount of abrasive material entering the seal cavity and potentially compromising the integrity of the seal.

TECHNICAL FIELD

This disclosure relates generally to machines having track-typeundercarriages and, in particular, to track carrier rollers in suchmachines having seal packing guards to impede compaction of materialwithin the seal cavity of the carrier roller.

BACKGROUND

Track-type machines are used in a wide variety of rugged serviceenvironments. The use of ground engaging tracks rather than wheels canprovide enhanced traction, stability, and robustness to a machine systemover what might otherwise be available. A typical undercarriage systemin a track-type machine includes a plurality of track shoes coupledtogether in an endless track chain by way of a set of track links, andextending about a drive sprocket and one or more rotatable idlers. Thetrack assembly provides better mobility on uneven ground and typicallyrenders excellent traction while spreading the weight of the machineover a large area. Mining, construction, landfills, forestry, and stillother service environments are notable examples of where track-typemachines are advantageously used.

During operation, the movement of the track-type machine typicallycauses the track assemblies to pick up dirt and debris or any outlyingmaterial as it makes contact with the ground, only to have the materialdeposited on the track frame and subsequently on the other components ofthe track-type machine. In these environments, and particularly inlandfills, abrasive materials are present at most worksites wheretrack-type machines are used. This may result in an increased machineweight, more friction forces between the moving components in the trackassemblies and increased machine wear. Wear is generally caused as theaccumulated material results in an abrasive action on the components ofthe machine.

One area where such accumulation occurs is in the seal cavities ofrotating components such as carrier rollers, track rollers, idlerrollers, sprockets and the like, all of which may be encompassed by theterm “roller” as used herein. As one example, carrier rollers extendabove the track frame and support the track chain between the sprocketand an idler roller to prevent slack in or sagging of the track chain.Carrier rollers are typically supported by a carrier stand extendingfrom the track frame and an axle or shaft extending from the carrierstand. Oil, grease or other lubricants disposed in a space between acarrier roller and its shaft reduce friction between the components.Annular or toroidal seals, such as O-rings, may be used to retain thelubricant in the space, but a seal cavity may place the seals in fluidcommunication with the ambient atmosphere surrounding the carrierroller. When operating in the environments described above, abrasivematerial may accumulate in the seal cavity and eventually displace theseal or abrade the seal resulting in the loss of lubricant and ultimatefailure of the carrier roller. In some environments, refuse such astrash bags and other plastic bags, wire, video cassette tape and thelike can enter the cavity wrap around the seals. In view of thesesituations, a need exists for an improved configuration of the trackcarrier roller that prevents or, at a minimum, retards the accumulationof abrasive material in the seal cavity of the roller.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a roller assembly is disclosed.The roller assembly includes a roller shaft and a roller rotatablymounted on the roller shaft with a first end of the roller shaftextending beyond an outward surface of the roller. The roller and theroller shaft define a lubricant reservoir there between, and with theoutward surface of the roller defining an outward rim of the roller,wherein the outward rim comprises an annular inner surface having atleast two inner diameter portions having decreasing inner diameters foreach of the at least two inner diameter portions as the annular innersurface extends inwardly from the outward surface of the roller. Theroller assembly further includes an annular seal disposed proximate thefirst end of the roller shaft and between the roller and the rollershaft and forming a substantially water-tight seal of the lubricantreservoir, and an annular collar disposed on the first end of the rollershaft and received in the outward rim of the roller. The annular collarincludes an annular outer surface having at least two outer diameterportions having decreasing outer diameters for each of the at least twoouter diameter portions as the annular outer surface extends inwardlyfrom an annular outer surface of the annular collar, wherein each of theat least two outer diameter portions of the annular outer surfacecorresponds to one of the at least two inner diameter portions of theannular inner surface of the outward rim, and the outward rim of theroller and the annular outer surface of the annular collar define a sealcavity placing the annular seal in fluid communication with an ambientatmosphere surrounding the roller.

In another aspect of the present disclosure, a roller assembly isdisclosed. The roller assembly includes a roller shaft, a rollerrotatably mounted on the roller shaft with a first end of the rollershaft extending beyond an outward surface of the roller, with the rollerand the roller shaft defining a lubricant reservoir there between, andwith the outward surface of the roller defining an outward rim of theroller, wherein the outward rim comprises an annular inner surface. Theroller assembly further includes an annular seal disposed proximate thefirst end of the roller shaft and between the roller and the rollershaft and forming a substantially water-tight seal of the lubricantreservoir, and an annular collar disposed on the first end of the rollershaft and received in the outward rim of the roller. The annular collarincludes an annular outer surface, wherein the annular outer surface ofthe annular collar and the annular inner surface of the outward rimdefine a seal cavity placing the annular seal in fluid communicationwith an ambient atmosphere surrounding the roller, and a flangeextending radially outward from the annular outer surface of the annularcollar beyond the seal cavity and over the outward surface of theroller.

In a further aspect of the present disclosure, a roller assembly isdisclosed. The roller assembly includes a roller shaft, a rollerrotatably mounted on the roller shaft with a first end of the rollershaft extending beyond an outward surface of the roller, the roller andthe roller shaft defining a lubricant reservoir there between, and withthe outward surface of the roller defining an outward rim of the roller,wherein the outward rim comprises an annular inner surface, an annularseal disposed proximate the first end of the roller shaft and betweenthe roller and the roller shaft and forming a substantially water-tightseal of the lubricant reservoir, and an annular collar disposed on thefirst end of the roller shaft and received in the outward rim of theroller. The annular collar includes an annular outer surface, whereinthe annular outer surface of the annular collar and the annular innersurface of the outward rim define a seal cavity placing the annular sealin fluid communication with an ambient atmosphere surrounding theroller, and a plurality of teeth circumferentially spaced about theannular outer surface of the annular collar and extending outwardly fromthe annular outer surface of the annular collar past a gap between theannular outer surface of the annular collar and the annular innersurface of the outward rim.

Additional aspects are defined by the claims of this patent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of a track-type machine having a trackcarrier roller in accordance with the present disclosure;

FIG. 2 is a partial sectional side view of a track carrier roller of themachine of FIG. 1;

FIG. 3 is a partial sectional side view of a track carrier roller ofFIG. 2 with a first embodiment of a seal packing guard in accordancewith the present disclosure;

FIG. 4 is a partial sectional side view of a track carrier roller ofFIG. 2 with an alternative embodiment of a seal packing guard inaccordance with the present disclosure;

FIG. 5 is a partial sectional side view of an embodiment of a trackcarrier roller in accordance with the present disclosure for the machineof FIG. 1;

FIG. 6 is an isometric view of the track carrier roller of FIG. 2 withan alternative embodiment of a collar functioning as a seal packingguard;

FIG. 7 is a cross-sectional view of the track carrier roller of FIG. 6taken through line 7-7;

FIG. 8 is an isometric view of the track carrier roller of FIG. 2 with afurther alternative embodiment of a seal packing guard;

FIG. 9 is a cross-sectional view of the track carrier roller of FIG. 8taken through line 9-9;

FIG. 10 is an isometric view of the track carrier roller of FIG. 2 witha still further alternative embodiment of a collar functioning as a sealpacking guard;

FIG. 11 is a cross-sectional view of the track carrier roller of FIG. 10taken through line 11-11;

FIG. 12 is a cross-sectional view of the track carrier roller of FIG. 6taken through line 7-7 with an alternative embodiment of the innersurface of the carrier roller;

FIG. 13 is an isometric view of the track carrier roller of FIG. 2 withanother alternative embodiment of a collar functioning as a seal packingguard;

FIG. 14 is a cross-sectional view of the track carrier roller of FIG. 13taken through line 14-14; and

FIG. 15 is a front view of the track carrier roller of FIG. 13.

DETAILED DESCRIPTION

Although the following text sets forth a detailed description ofnumerous different embodiments, it should be understood that the legalscope of protection is defined by the words of the claims set forth atthe end of this patent. The detailed description is to be construed asexemplary only and does not describe every possible embodiment sincedescribing every possible embodiment would be impractical, if notimpossible. Numerous alternative embodiments could be implemented, usingeither current technology or technology developed after the filing dateof this patent, which would still fall within the scope of the claimsdefining the scope of protection.

It should also be understood that, unless a term is expressly defined inthis patent using the sentence “As used herein, the term ‘______ ’ ishereby defined to mean . . . ” or a similar sentence, there is no intentto limit the meaning of that term, either expressly or by implication,beyond its plain or ordinary meaning, and such term should not beinterpreted to be limited in scope based on any statement made in anysection of this patent (other than the language of the claims). To theextent that any term recited in the claims at the end of this patent isreferred to in this patent in a manner consistent with a single meaning,that is done for sake of clarity only so as to not confuse the reader,and it is not intended that such claim term be limited, by implicationor otherwise, to that single meaning. Finally, unless a claim element isdefined by reciting the word “means” and a function without the recitalof any structure, it is not intended that the scope of any claim elementbe interpreted based on the application of 35 U.S.C. §112, sixthparagraph.

Referring to FIG. 1, a track-type machine 10 may embody a mobile machinethat performs some type of operation associated with an industry such asmining, construction, farming, transportation, waste handling or anyother industry known in the art. For example, the machine 10 may be anearth moving machine such as a track-type tractor or other suitablemachine. The machine 10 may include an implement system 12 configured toadjust the position or orientation of an implement such as a tractorblade 14, a drive system in the form of a track undercarriage 16 forpropelling the machine 10, a power source 18 that provides power to theimplement system 12 and the undercarriage 16, and an operator station 20for operator control of the implement system 12 and the undercarriage16. Though a track-type tractor is illustrated, the packing guards andcollars disclosed herein may be implemented in any other types ofmachines having an undercarriage, such as material loaders, excavatorsand the like.

Power source 18 may embody an engine such as, for example, a dieselengine, a gasoline engine, a gaseous fuel-powered engine or any othertype of combustion engine known in the art. It is contemplated thatpower source 18 may alternatively embody a non-combustion source ofpower such as a fuel cell, a power storage device, or another sourceknown in the art. Power source 18 may produce a mechanical or electricalpower output that may then be converted to hydraulic or pneumatic powerfor moving the implement system 12, and converted into drive torque byan appropriate power transmission assembly (not shown) to drive a track22 of the undercarriage 16.

The undercarriage 16 may be a standard track drive system known in theart and includes a roller frame 24 connected to a body 26 of the machine10 and having a drive sprocket 28 and one or more idler pulleys 30pivotally connected thereto. The track 22 is supported by the sprocket28 and idler pulleys 30, but may not be taught so that the track 22 maymove to provide stability for the machine 10 as it traverses uneventerrain. Pairs of track rollers 32 pivotally connected to the rollerframe 24 by bogies 34 support the machine 10 and absorb vibrations asthe machine 10 travels over the uneven terrain. Above the roller frame24, the portion of the track 22 between the sprocket 28 and front idlerpulley 30 is supported by at least one carrier roller 36. The carrierroller 36 is rotatably mounted to a carrier stand 38 extending upwardlyfrom the roller frame 24 so that the carrier roller 36 rotates as thetrack 22 moves between the sprocket 28 and the idler pulley 30. Theundercarriage 16 illustrated herein is an elevated sprocket-typeundercarriage, but those skilled in the art will understand that theconcepts disclosed herein may be implemented in other types ofundercarriage such as low sprocket undercarriages having a sprocket 28and a single idler pulley 30.

FIG. 2 illustrates an example of the carrier roller 36 for which sealpacking guards in accordance with the present disclosure may beimplemented. This implementation of the seal packing guards and collarsin the carrier roller 36 is exemplary only. The seal packing guards andcollars in accordance with the present disclosure may be implemented inother rotating components mounted on a shaft, such as track rollers,idler pulleys, sprockets and the like, that collectively are encompassedby the term “roller.” The carrier roller 36 is rotatably mounted to thecarrier stand 38 by an axial roller shaft or axle 40 extending out ofthe carrier roller 36 beyond an outward surface of the carrier roller 36and received and retained by the carrier stand 38. The carrier stand 38engages the roller shaft 40 to prevent rotation of the roller shaft 40relative to the carrier stand 38 as the carrier roller 36 rotates aboutthe roller shaft 40. The carrier roller 36 is illustrated and describedwith the cantilevered shaft 40, but rollers or other components in whichseal packing guards and collars are implemented may have the shaft 40extend out of both sides of the roller 36 and be dually supported by theroller frame 24 or other frame of the machine 10.

Portions of an inner surface 42 of the carrier roller 36 and an outersurface 44 of the roller shaft 40 define a lubricant reservoir 46 therebetween in which a lubricant such as oil or grease is disposed tolubricate the moving components of the carrier roller 36. The carrierroller 36 is rotatably mounted to the roller shaft 40 by bearings, suchas a pair of thrust bearings 48, 50. Each thrust bearing 48, 50 may havean inner race 52 mounted on the outer surface 44 of the roller shaft 40,an outer race 54 mounted to the inner surface 42 of the carrier roller36 for rotation there with, and a plurality of tapered roller bearings56 allowing relative movement of the outer races 54 with respect to theinner races 52 and allowing the thrust bearings 50 to bear radial andthrust loads that occur as the track 22 moves over the carrier roller36. The surfaces 42, 44 and a race lock plate 58 connected to an end ofthe roller shaft 40 by fasteners 60 are configured to engage the innerraces 52 and the outer races 54 to maintain radial alignment of thepairs of inner races 52 and outer races 54.

The lubricant reservoir 46 is closed and sealed at one end by an end cap62 received in a first outward rim 64 of the inner surface 42 of thecarrier roller 36. The end cap 62 and the first outward rim 64 engage toform a substantially water-tight seal to prevent leakage of thelubricant from the reservoir 46. The end cap 62 includes a fill hole 66and corresponding fill plug 67 that can be removed to replenish thelubricant in the reservoir 46.

The opposite end of the lubricant reservoir 46 is closed by an annularcollar 68 in combination with an appropriate seal mechanism for forminga seal between two components moving relative to each other. The annularcollar 68 may have a circular opening having an inner diameterdimensioned to correspond with an outer diameter of a correspondingportion of the outer surface 44 of the roller shaft 40. The collar 68may also have a generally cylindrical outer surface 70 having an outerdiameter dimensioned smaller than an inner diameter of a correspondingsecond outward rim 72 of the carrier roller 36 to create a gap therebetween.

As shown in FIG. 2, the seal at the collar 68 and outward rim 72 may bea stationary metal face seal set 74. The seal set 74 may have an outwardportion with a first annular seal block 76 mounted on the outer surface44 of the roller shaft 40, and a first annular or toroidal seal 78disposed between the first seal block 76 and a cylindrical inner surface80 of the collar 68 to form a substantially water-tight seal therebetween. The seal set 74 also has a complementary inward portion with asecond annular seal block 82 mounted to the outer surface 44 of theroller shaft 40 inward of the first seal block 76, and a second annularor toroidal seal 84 disposed between the second seal block 82 and acorresponding portion of the inner surface 42 of the carrier roller 36to form a substantially water-tight seal there between to preventlubricant from the reservoir 46 from leaking into an annular seal cavity86 defined by the outer surface 70 of the collar 68 and the secondoutward rim 72 of the carrier roller 36.

As will be apparent from FIG. 2, the seal cavity 86 opens to theexterior of the carrier roller 36 and places the seal set 74 in fluidcommunication with the ambient atmosphere surrounding the carrier roller36. During use of the machine 10 in environments such as landfillshaving dust and loose abrasive materials, debris is churned up by thetracks 22 and can enter the seal cavities 86 of the carrier rollers 36.Over time, material accumulates in the seal cavity 86 and becomescompacted. The compacted material eventually traverses the seal cavity86 and engages the seals 78, 84 of the seal set 74. Over time, thecompacted material can displace the seals 78, 84 or abrade the seals 78,84, resulting in leaks of lubricant and ultimately to the failure of thecarrier roller 36.

FIG. 3 illustrates the carrier roller 36 as described above providedwith an embodiment of an annular seal packing guard 90 in accordancewith the present disclosure that retards the build-up of compactedmaterial in the seal cavity 86. The seal packing guard 90 shown in FIG.3 includes a first annular guard portion 92 connected to the secondoutward rim 72 of the carrier roller 36, and a second annual guardportion 94 connected to the first annular guard portion 92 opposite thecarrier roller 36. The first guard portion 92 includes an annular outersurface 96 having an outer diameter and an annular inner surface 98having an inner diameter that is greater than the outer diameter of theouter surface 70 of the collar 68 so that the first guard portion 92does not engage the collar 68 as the carrier roller 36 rotates about theroller shaft 40. An inward surface 100 of the first guard portion 92faces and engages the outward rim 72 and is secured thereto by welds,adhesive or other appropriate fastening mechanisms. An outward surface102 of the first guard portion 92 is disposed opposite the inwardsurface 100, with the first guard portion 92 having a thickness thatextends the outward surface 102 axially beyond the collar 68.

The second guard portion 94 includes an annular outer surface 104 havingan outer diameter that is approximately equal to the outer diameter ofthe outer surface 96 of the first guard portion 92 so that the outersurfaces 96, 104 are approximately aligned. An annular inner surface 106has an inner diameter that is smaller than the outer diameter of theouter surface 70 of the collar 68 so that the second guard portion 94overlays the seal cavity 86, and the inner diameter is larger than anouter diameter of a corresponding portion of the outer surface 44 of theroller shaft 40 so that the inner surface 106 does not engage the rollershaft 40 as the carrier roller 36 rotates about the roller shaft 40. Aninward surface 108 of the second guard portion 94 faces and engages theoutward surface 102 of the first guard portion 92 and is secured theretoby welds, adhesive or other appropriate fastening mechanisms. An outwardsurface 110 of the second guard portion 94 is disposed opposite theinward surface 108, with the second guard portion 94 having a thicknessthat preserves a gap between the seal packing guard 90 and the carrierstand 38 so that the carrier roller 36 and seal packing guard 90 arefree to rotate about the roller shaft 40.

The annular guard portions 92, 94 of the seal packing guard 90 may befabricated from any appropriate material that will withstand the impactsof the abrasive materials of the work environment without fracturing,wearing away due to erosion, or detach from the carrier roller 36.Though the seal packing guard 90 is illustrated and described herein asbeing formed from separate components in the guard portions 92, 94, theseal packing guard 90 may be fabricated as a single unitary componenthaving dimensions as described above. The unitary seal packing guard 90may be formed from any appropriate process such as stamping, forging,molding, casting and the like that is capable of forming the geometry ofthe seal packing guard 90 described herein.

FIG. 4 illustrates an alternative embodiment of a seal packing guard 120in accordance with the present disclosure. The seal packing guard 120may be formed from a piece of stamped steel or other appropriate metal,and include a first annular plate 122, a second annular plate 124, andan intermediate transition or spacing portion 126. The first annularplate 122 of the seal packing guard 120 is shaped similar to a washerand has an outer diameter and an inner diameter that is greater than theouter diameter of the outer surface 70 of the collar 68 so that aninward surface 128 of the seal packing guard 120 does not engage thecollar 68 as the carrier roller 36 rotates about the roller shaft 40. Aportion of the inward surface 128 at the first annular plate 122 facesand engages the outward rim 72 and is secured thereto by welds 130,adhesive or other appropriate fastening mechanisms.

The second annular plate 124 of the seal packing guard 120 is alsoshaped similar to a washer and has an inner diameter that is larger thanan outer diameter of a corresponding portion of the outer surface 44 ofthe roller shaft 40 so that the inner surface 106 does not engage theroller shaft 40 as the carrier roller 36 rotates about the roller shaft40. At the same time, the inner diameter of the second annular plate 124is smaller than the outer diameter of the outer surface 70 of the collar68 so that the second annular plate 124 overlays the seal cavity 86 toat least partially shelter the seals 78, 84 from abrasive material. Thesecond annular plate 124 is connected to the first annular plate 122 bythe transition portion 126. The transition portion 126 is configured toextend beyond the collar 68 so that the portion of the inward surface128 of the seal packing guard 120 at the second annular plate 124overlays the collar 68 without engaging the collar 68. At the same time,a portion of an outward surface 132 of the seal packing guard 120 at thesecond annular plate 124 preserves a gap between the seal packing guard120 and the carrier stand 38 so that the carrier roller 36 and sealpacking guard 120 are free to rotate about the roller shaft 40.

The intermediate transition portion 126 as illustrated is shaped togenerally conform to the outer contour of the collar 68 to maintainseparation of the inward surface 128 from the collar 68. Those skilledin the art will understand that the portion 126 may have any otherappropriate shape that will connect the second annular plate 124 to thefirst annular plate 122 in a manner that maintains the spacing of theseal packing guard 120 from the carrier stand 38, the roller shaft 40,and the collar 68. Moreover, though the annular plates 122, 124 andtransition portion 126 are illustrated and described as being integrallyformed from a single piece of metal in a stamping process, one or all ofthe portions 122-126 may be formed separately and later connected viaany appropriate connection method to form the seal packing guard 120.

In addition or as an alternative to providing the seal packing guards90, 120 to retard the accumulation of compacted material in the sealcavity 86, modifications may be made to the carrier roller 36 and thecollar 68 to isolate the seal cavity 86 from the ambient atmospheresurrounding the carrier roller 36. FIG. 5 illustrates one alternativeembodiment of the carrier roller 36 and the collar 68 that increases thedistance that the abrasive material must traverse to reach the seals 78,84. In this embodiment, the geometries of an outer surface 140 of thecollar 68 and the corresponding inner surface 142 defining the outwardrim 72 are modified to form a labyrinth there between that must betraversed to enter the seal cavity 86. The outer surface 140 of thecollar 68 may include a series of decreasing outer diameters as theouter surface 140 proceeds inwardly into the carrier roller 36.Consequently, the outer surface 140 may have a first outer diameterportion 144 extending inwardly and having a largest outer diameter. Thefirst outer diameter portion 144 transitions to a second outer diameterportion 146 having a smaller outer diameter than the first outerdiameter portion 144, which then transitions into a third outer diameterportion 148 having a still smaller outer diameter.

To match the transitioning of the outer surface 140 of the collar 68 tosmaller outer diameters, the inner diameter of the inner surface 142 ofthe outward rim 72 progressively decreases as it approaches the sealcavity 86 from the exterior of the carrier roller 36. Consequently, theinner surface 142 has a first inner diameter portion 150 with an innerdiameter that is greater than the outer diameter of the first outerdiameter portion 144 of the outer surface 140 and extends axiallyinwardly by a greater distance than the first outer diameter portion144. The first inner diameter portion 150 transitions to a second innerdiameter portion 152 having an inner diameter smaller than the innerdiameter of the first inner diameter portion 150 but greater than theouter diameter of the second outer diameter portion 146 of the outersurface 140. The second inner diameter portion 152 extends furtheraxially inwardly than the second outer diameter portion 146 to atransition to a third inner diameter portion 154 having a still smallerinner diameter that the inner diameter of the second inner diameterportion 152. The third portions 146, 154 of the surfaces 140, 142,respectively, combine to define an entrance to the seal cavity 86.

The cooperating geometries of the outward rim 72 of the carrier roller36 and the outer surface 140 of the collar 68 are exemplary, and othergeometries functioning to increase the distance to be traversed by theabrasive material are contemplated. For example, the number ofincremental decreases in the outer surface 140 may be increased ordecreased from the three outer diameter portions 144-148 shown in FIG.5, and the axial lengths of the portions 144-148 and 150-154 may beincreased or decreased. The amount of change in the diameters of thesurfaces 140, 144 may also be varied as desired. Moreover, whereas thetransition regions between the portions 144-148 and 150-154 are shown asbeing generally planar and perpendicular to the roller shaft 40, theregions may be oriented at non-perpendicular angles relative to theroller shaft 40. The length of the labyrinth leading to the seal cavity86 may further be increased by providing the transition surfaces withcomplimentary non-planar shapes, such as by providing recesses orgrooves in the outer surface between the outer diameter portions 144-148and corresponding ribs or ridges in the inner surface between the innerdiameter portions 150-154, or vice versa. Such arrangements direct theabrasive material through non-linear paths while still allowing thecollar 68 to be inserted into the outward rim 72 without the collar 68and carrier roller 36 engaging to impede the rotation of the carrierroller 36. Additional geometric configurations of the surfaces 140, 142to retard or delay the flow of abrasive material to the seal cavity 86will be apparent to those skilled in the art and are contemplated by theinventors as having use in carrier rollers 36 in accordance with thepresent disclosure.

FIGS. 6 and 7 illustrate another alternative embodiment where the sealpacking guard functionality is integrated into a modified collar 160that restricts the flow of material into the seal cavity 86. The collar160 includes a flange 162 extending radially outward from an outersurface 164 of the collar 160 over the outward surface 72 and beyond theseal cavity 86 and thereby increasing the length of the labyrinthleading to the seal cavity 86. The flange 162 includes a plurality ofcircumferentially spaced apertures 166 there through to allow relativelysmall sized material and debris to flow into and, more critically, outof the seal cavity 86. As shown, the apertures 166 may be aligned withthe entrance to the seal cavity 86 defined by the outer surface 164 ofthe collar 160 and the outward surface 72 of the carrier roller 36.Alternatively, the apertures 166 may be radially positioned on theflange 162 inwardly or outwardly to offset the apertures 166 from theseal cavity 86 if necessary to produce a desired flow of material fromthe seal cavity 86.

The apertures 166 may be provided in varying sizes, and do notnecessarily need to be round as illustrated herein. For example, theapertures 166 may be radial slots, circumferential slots, squares,triangles or any other desired geometric configuration to facilitate theflow of material out of the seal cavity 86. The illustrated apertures166 have a generally constant diameter there through, but the apertures166 may also be tapered or countersunk with a minimum diameter proximatethe outward surface 72 and seal cavity 86, and a maximum diameter at theoutward side of the collar 160 opposite the seal cavity 86. The taperingof the apertures 166 may restrict the flow of material through theapertures 166 into the seal cavity 86, while at the same time promotethe flow of material out of the seal cavity 86. The extended flange 162and the apertures 166 of the collar 160 allow material such as mud anddirt that inevitably accumulate to exit the seal cavity 86, whilepreventing larger materials, strings, wire, video cassette tape, plasticbags and the like that create a greater risk of damage to the seals 78,84 from entering the seal cavity 86.

The outer surface 164 of the collar 160 may be similarly configured toproduce a desired flow of material into and out of the seal cavity 86.As shown, the outer surface 164 may be tapered from a maximum outerdiameter proximate the seal cavity 86 to a minimum outer diameterproximate the flange 162. With this geometry of the outer surface 164,the gap between the outer surface 164 and the outward rim 72 increasesas the outer surface 164 extends from the seal cavity 86 toward theflange 162 to encourage flow of material out of the seal cavity 86. Asshown in FIG. 12, a portion 168 of the outward rim 72 radially alignedwith the outer surface 164 may be tapered in a manner opposite the outersurface 164 from a minimum outer diameter proximate the seal cavity 86to a maximum outer diameter proximate the exterior of the carrier roller36. The tapering of the portion 168 of the outward rim 72 furtherfacilitates the flow of material out of the seal cavity 86 in general.Moreover, the downward slope of the portion 168 proximate the lower endof the carrier roller 36 allows loose material to feed out of the sealcavity 86 under the force of gravity before mud, water or other cohesivemedium aggregates the material within the seal cavity 86. Of course,those skilled in the art will understand that tapering of the outersurfaces of the collars and corresponding portions of the outward rimsas shown in FIGS. 7 and 12 may be implemented in any of the embodimentsillustrated herein or other implementations of seal packing guards, theimplementation of which is contemplated by the inventors.

FIGS. 8 and 9 illustrate a further alternative embodiment of a sealpacking guard 170 in accordance with the present disclosure that mayhave particular application in mud packing environments in retarding thebuild-up of compacted material in the seal cavity 86. The seal packingguard 170 shown in FIGS. 8 and 9 includes an annular outer ring 172connected to the second outward rim 72 of the carrier roller 36, and aplurality of circumferentially spaced fingers 174 extending radiallyinwardly from an annular inner surface 176 of the outer ring 172 so thatthe fingers 174 overlay the gap between the outer surface 70 and theoutward rim 72 forming the channel leading to the seal cavity 86. Theouter ring 172 includes an annular outer surface 178 having an outerdiameter, and the annular inner surface 176 has an inner diameter. Theouter ring 172 is secured to the outward rim 72 by welds, bolts,adhesive or other appropriate fastening mechanisms. The outer ring 172and the fingers 174 are dimensioned so that the fingers 174 are disposedaxially outward beyond the collar 68 so that the fingers 174 do notengage the collar 68 as the carrier roller 36 and, correspondingly, theseal packing guard 170 rotate about the shaft 40 during use.

The fingers 174 may have any appropriate geometry to scrape or otherwisedivert material from entering the seal cavity 86 as the carrier roller36 and seal packing guard 170 rotate. In the illustrated embodiment,each of the fingers 174 has a generally triangular shape that tapersfrom a relatively wide base of the triangle at the inner surface 176 ofthe outer ring 172 to a point at an inward end of the finger 174. Eachof the fingers 174 may also have chamfered perimeter edges taperinginward from the side facing the collar 70 to the outward side of thefinger 174 to assist in diverting material away from the gap between theouter surface 70 and the outward rim 72. The space between adjacentfingers 174 of the seal packing guard 170 may be dimensioned largeenough to allow egress from the seal cavity 86 for material that flowsin past the scraping fingers 174 during rotation of the carrier roller36.

The concept of the scraping fingers 174 as described above may beimplemented in the collar without the necessity of a separate sealpacking guard component being attached to the roller assembly. As shownin FIGS. 10 and 11, a collar 180 may include an annular disk 182 havingan outer surface 184 forming a gap with the outward rim 72 leading tothe seal cavity 86. A plurality of circumferentially spaced teeth 186may extend outwardly from the outer surface 184 of the collar 180 suchthat the teeth 186 overlay the gap between the outer surface 184 and theoutward rim 72. The teeth 186 may have any appropriate shape tofacilitate scraping of material as the carrier roller 36 rotates pastthe teeth 186, such as a triangular shape that tapers from a relativelywide base at the outer surface 184 of the collar 180 to a point at anoutward end of the tooth 186, or a relatively constant width as thetooth 186 extends from the outer surface 184 to an outward end of thetooth 186. Each of the teeth 186 may also have chamfered perimeter edgestapering inward from the side facing the outward rim 72 to the outwardside of the tooth 186 to create a scraping edge causing the scrapedmaterial to flow away from outward rim 72. Though not shown, the outersurface 184 and the corresponding radially aligned portion of theoutward rim 72 may be tapered as described with regards to FIGS. 7 and12 to further promote the flow of material out of the seal cavity 86.

FIGS. 13-15 illustrate a modification of the embodiment of FIGS. 10 and11 providing improved flow of material out of the seal cavity 86.Similar to the collar 180 of FIGS. 10 and 11, a collar 190 may includean annular disk 192 having an outer surface 184 forming a gap with theoutward rim 72 leading to the seal cavity 86. A plurality ofcircumferentially spaced teeth 196 may extend outwardly from the outersurface 194 of the collar 190 such that the teeth 196 overlay the gapbetween the outer surface 194 and the outward rim 72. The outer surface194 of the collar 190 is configured to produce the desired flow ofmaterial into and out of the seal cavity 86 by being tapered from amaximum outer diameter proximate the seal cavity 86 to a minimum outerdiameter at an outward side of the annular disk 192. A portion 198 ofthe outward rim 72 radially aligned with the outer surface 194 istapered in a manner opposite the outer surface 194 from a minimum outerdiameter proximate the seal cavity 86 to a maximum outer diameterproximate the exterior of the carrier roller 36. The complimentarytapering of both the outer surface 194 and the outward rim 72 furtherfacilitates the flow of material out of the seal cavity 86, and thedownward slope of the portion 198 of the outward rim 72 proximate thelower end of the carrier roller 36 allows loose material to feed out ofthe seal cavity 86 under the force of gravity. The teeth 196 may havechamfered perimeter edges as discussed above. Additionally, as shownmore clearly in FIG. 15, the teeth 196 may have a reverse triangularshape that widens from a relatively narrow base at the outer surface 194of the collar 190 to a relatively wide outward end. Dimensioned asshown, the facing edges of adjacent teeth 196 may be approximatelyparallel. Of course, other relative orientations of the facing edges ofadjacent teeth 196 will be apparent and are contemplated by theinventors.

INDUSTRIAL APPLICABLITY

The seal packing guards 90, 120, 170 and the configurations of thecarrier rollers 36 and collars 68, 160, 180 disclosed herein serve toprolong the useful life of the carrier rollers 36 by protecting the sealcavity 86 from the adverse affects of engagement by compacted abrasivematerials. The arrangements of the seal packing guards 90, 120 impedethe accumulation of compacted material within the seal cavity 86 due tothe proximity of the seal packing guard 90 to the carrier stand 38 androller shaft 40. The increased lengths of the seal cavity 86 provided bythe seal packing guards 90, 120 function to forestall the impingement ofthe compacted material on the seals 76, 84 that causes prematuredisplacement of the seals 76, 84 or abrasion of the seals 76, 84resulting in leakage of the lubricant and premature failure of thecarrier roller 36.

The complimentary geometries of the outer surface 140 of the collar 68and the inner surface 142 of the outward rim 72 of the carrier roller 36similarly prolong the useful life of the carrier roller 36 by increasingthe distance to be traversed by the abrasive material to reach the sealcavity 86. Additional complimentary geometries are possible andcontemplated for increasing the distance to the seal cavity 86 whileallowing the collar 68 to be inserted into the outward rim 72 withoutinterfering with the rotation of the carrier roller 36 about the rollershaft 40. Moreover, though not explicitly illustrated herein, the sealpacking guards 90, 120 may be implemented in conjunction with thegeometries of the surfaces 140, 142 to establish labyrinths having morecomplexity and distance for the abrasive material to traverse beforeimpacting and compacting around the seals 76, 84.

The collars and/or seal packing guards may also be configured to allowbenign types of material to flow into and out of the seal cavity 86while preventing more destructive materials from entering the sealcavity 86 and engaging the seals 78, 84. Small materials may flow intoand out of the seal cavity 86 past the collars 70, 160, 180 and sealpacking guard 170. However, larger materials and objects such as wire,string, video cassette tape, plastic bags and the like that can getbound up in the seal cavity 86 are prevented from passing through to theseal cavity 86. By restricting and, for some materials, preventingpassage into the seal cavity 86, the integrity of the seals 78, 84 maybe preserved longer in the embodiments disclosed herein than forpreviously know rotating components, such as carrier rollers, trackrollers, idler pulleys, sprockets and the like, without seal packingguards and collars managing the material flow through the seal cavities86.

While the preceding text sets forth a detailed description of numerousdifferent embodiments, it should be understood that the legal scope ofprotection is defined by the words of the claims set forth at the end ofthis patent. The detailed description is to be construed as exemplaryonly and does not describe every possible embodiment since describingevery possible embodiment would be impractical, if not impossible.Numerous alternative embodiments could be implemented, using eithercurrent technology or technology developed after the filing date of thispatent, which would still fall within the scope of the claims definingthe scope of protection.

What is claimed is:
 1. A roller assembly, comprising a roller shaft; aroller rotatably mounted on the roller shaft with a first end of theroller shaft extending beyond an outward surface of the roller, theroller and the roller shaft defining a lubricant reservoir therebetween, and with the outward surface of the roller defining an outwardrim of the roller, wherein the outward rim comprises an annular innersurface having at least two inner diameter portions having decreasinginner diameters for each of the at least two inner diameter portions asthe annular inner surface extends inwardly from the outward surface ofthe roller; an annular seal disposed proximate the first end of theroller shaft and between the roller and the roller shaft and forming asubstantially water-tight seal of the lubricant reservoir; and anannular collar disposed on the first end of the roller shaft andreceived in the outward rim of the roller, the annular collar comprisingan annular outer surface having at least two outer diameter portionshaving decreasing outer diameters for each of the at least two outerdiameter portions as the annular outer surface extends inwardly from anannular outer surface of the annular collar, wherein each of the atleast two outer diameter portions of the annular outer surfacecorresponds to one of the at least two inner diameter portions of theannular inner surface of the outward rim, and the outward rim of theroller and the annular outer surface of the annular collar define a sealcavity placing the annular seal in fluid communication with an ambientatmosphere surrounding the roller.
 2. The roller assembly of claim 1,wherein the at least two inner diameter portions of the annular innersurface comprises three inner diameter portions and the at least twoouter diameter portions of the annular outer surface comprises threeouter diameter portions.
 3. The roller assembly of claim 1, wherein theannular inner surface of the outward rim comprises a transition portionbetween each pair of adjacent inner diameter portions having a planarsurface that is perpendicular to the roller shaft, and wherein theannular outer surface of the annular collar comprises a transitionportion between each pair of adjacent outer diameter portions having aplanar surface that is perpendicular to the roller shaft.
 4. The rollerassembly of claim 3, wherein the planar surfaces of the transitionportions are perpendicular to the roller shaft.
 5. The roller assemblyof claim 1, wherein the annular inner surface of the outward rimcomprises a transition portion between each pair of adjacent innerdiameter portions having a raised annular rib, and wherein the annularouter surface of the annular collar comprises a transition portionbetween each pair of adjacent outer diameter portions having a recessedannular groove axially aligned with the raised annular rib of acorresponding transition portion of the annular inner surface.
 6. Theroller assembly of claim 1, comprising a seal packing guard comprising:a first annular guard portion having an inward surface connected to theoutward surface of the roller and extending axially outwardly from theinward surface to an outward surface beyond an outer surface of theannular collar, the first annular guard portion having an annular innersurface with an inner diameter that is greater than an outer diameter ofthe annular outer surface of the annular collar, and a second annularguard portion connected to the first annular guard portion and having aninner surface with an inner diameter that is greater than an outerdiameter of the outer surface of the roller shaft proximate the firstend, and is less than the outer diameter of the annular outer surface ofthe annular collar, and the second annular guard portion having aninward surface defining, in cooperation with the outer surface of theannular collar, a seal cavity extension in fluid communication with theseal cavity.
 7. A roller assembly, comprising a roller shaft; a rollerrotatably mounted on the roller shaft with a first end of the rollershaft extending beyond an outward surface of the roller, the roller andthe roller shaft defining a lubricant reservoir there between, and withthe outward surface of the roller defining an outward rim of the roller,wherein the outward rim comprises an annular inner surface; an annularseal disposed proximate the first end of the roller shaft and betweenthe roller and the roller shaft and forming a substantially water-tightseal of the lubricant reservoir; and an annular collar disposed on thefirst end of the roller shaft and received in the outward rim of theroller, the annular collar comprising: an annular outer surface, whereinthe annular outer surface of the annular collar and the annular innersurface of the outward rim define a seal cavity placing the annular sealin fluid communication with an ambient atmosphere surrounding theroller, and a flange extending radially outward from the annular outersurface of the annular collar beyond the seal cavity and over theoutward surface of the roller.
 8. The roller assembly of claim 7,wherein the annular collar comprises a plurality of apertures extendingthrough the flange from an inward surface of the flange to an outwardsurface of the flange and being circumferentially spaced about theflange.
 9. The roller assembly of claim 8, wherein the plurality ofapertures are axially aligned with an entrance to the seal cavity. 10.The roller assembly of claim 8, wherein each of the plurality ofapertures has a circular cross-section.
 11. The roller assembly of claim8, wherein each of the plurality of apertures has a non-circularcross-section.
 12. The roller assembly of claim 8, wherein each of theplurality of apertures is tapered such that the aperture has a minimumcross-sectional area proximate the inward surface of the flange and amaximum cross-sectional area proximate the outward surface of theflange.
 13. The roller assembly of claim 7, wherein a portion of theannular outer surface of the annular collar is tapered from a maximumouter diameter proximate the annular seal to a minimum outer diameterproximate the flange.
 14. The roller assembly of claim 13, wherein aportion of the annular inner surface of the outward rim radially alignedwith the tapered portion of the annular outer surface of the annularcollar is tapered from a minimum outer diameter proximate the annularseal to a maximum outer diameter proximate the exterior of the roller.15. A roller assembly, comprising a roller shaft; a roller rotatablymounted on the roller shaft with a first end of the roller shaftextending beyond an outward surface of the roller, the roller and theroller shaft defining a lubricant reservoir there between, and with theoutward surface of the roller defining an outward rim of the roller,wherein the outward rim comprises an annular inner surface; an annularseal disposed proximate the first end of the roller shaft and betweenthe roller and the roller shaft and forming a substantially water-tightseal of the lubricant reservoir; and an annular collar disposed on thefirst end of the roller shaft and received in the outward rim of theroller, the annular collar comprising: an annular outer surface, whereinthe annular outer surface of the annular collar and the annular innersurface of the outward rim define a seal cavity placing the annular sealin fluid communication with an ambient atmosphere surrounding theroller, and a plurality of teeth circumferentially spaced about theannular outer surface of the annular collar and extending outwardly fromthe annular outer surface of the annular collar past a gap between theannular outer surface of the annular collar and the annular innersurface of the outward rim.
 16. The roller assembly of claim 15, whereineach of the plurality of teeth has a triangular shape that tapers from arelatively wide base at the annular outer surface of the annular collarto a point at an outward end of the tooth.
 17. The roller assembly ofclaim 15, wherein each of the plurality of teeth has a constant width asthe tooth extends from the annular outer surface of the annular collarto an outward end of the tooth.
 18. The roller assembly of claim 15,wherein each of the plurality of teeth has chamfered perimeter edgestapering inward from an inward side facing the seal cavity to an outwardside disposed opposite the inward side.
 19. The roller assembly of claim15, wherein a portion of the annular outer surface of the annular collaris tapered from a maximum outer diameter proximate the annular seal to aminimum outer diameter proximate the teeth.
 20. The roller assembly ofclaim 19, wherein a portion of the annular inner surface of the outwardrim radially aligned with the tapered portion of the annular outersurface of the annular collar is tapered from a minimum outer diameterproximate the annular seal to a maximum outer diameter proximate theexterior of the roller.
 21. The roller assembly of claim 15, wherein theannular outer surface of the annular collar is tapered from a maximumouter diameter proximate the annular seal to a minimum outer diameterproximate an outward side of the annular collar.
 22. The roller assemblyof claim 21, wherein a portion of the annular inner surface of theoutward rim radially aligned with the annular outer surface of theannular collar is tapered from a minimum outer diameter proximate theannular seal to a maximum outer diameter proximate the exterior of theroller.